#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
#define rep(i, a, b) for (int i = (a); i <= (b); i++)
#define per(i, a, b) for (int i = (a); i >= (b); i--)
#define endl '\n'
const int N = 2e5 + 5;

ll a, b;
ll extgcd(ll a, ll b, ll &x, ll &y) {
  if (b == 0) {
    x = 1, y = 0;
    return a;
  }
  ll d = extgcd(b, a % b, y, x);
  // b * y + (a - a / b * b) * x = d
  // a * x + b * (y - a / b * x) = d
  y -= a / b * x;
  return d;
}
ll f(ll a, ll b) {
  ll x, y;
  extgcd(a, b, x, y);
  // a * x + b * y = 1
  // X = k * b + x
  x %= b;
  if (x < 0) x += b;
  return x;
}
int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> a >> b;
  cout << f(a, b);
  return 0;
}